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Biomedical subjects

P Hubert

Publications and source records attributed to P Hubert.

At least 199 records · Page 11Linked to original sources
PubMed1988

One-Step Purification of a Lipolytic Enzyme from Bacillus pumilus by Mild Hydrophobic Interaction Chromatography on Polyoxyalkylene Glycol-Bound Sepharose 6B.

An esterase from Bacillus pumilus was obtained in a highly purified form, starting from a crude extract, by a new chromatographic technique requiring no detergent during the elution step. The stationary phase involved was mildly hydrophobic and was prepared by covalent immobilization of a polyoxyalkylene glycol onto Sepharose 6B.

Journal Article↗
PubMed1988

Interhemispheric subdural haematomas: seven cases and review of the literature.

Interhemispheric subdural haematoma (ISH) is a rare complication of head injury with only 19 cases reported since 1940, but it may also occur spontaneously (three cases). In both circumstances, clotting disorders are frequent (six cases). We have recorded seven cases (five traumatic, two spontaneous). Classically ISH is due to tearing of bridging veins or cortical contusions. In one of our cases, it was due to arterial bleeding from a pericallosal branch. CT scan shows that ISH may extend above the tentorium and on the hemispheric convexity. Mortality is high (35%). The best operative procedure is parasagittal craniotomy. Chronic interhemispheric subdural haematomas also occur.

Adult↗
PubMed1988

[The Pierre-Robin syndrome. Classification and new therapeutic approach].

Rhombencephalic failure of the suction-swallowing, excess of central and obstructive ventilatory arrests with hypoxia and hypercapnia, vagal hypertonia and esophagogastric motor abnormalities are the new clinical signs observed in children presenting with the Pierre Robin's syndrome. A therapeutic management adapted to each of the types I, II, III of the syndrome were defined and a good nursery-nursing allowed a reduction in the mortality-rate from 27 to 5%. Still considered by some as a malformative and glossoptosing disorder whose etiology is only bucco-pharyngeal in origin, this syndrome, common to numerous embryopathies, is a precocious embryonal abnormality of the brain stem neurogenesis, expressed by the dramatic failure of the physiological oro-ventilation system. This syndrome appears to be a peculiar form of dysautonomia of the brain stem development with an uncertain future, often transitory, isolated or associated but in the heart of pediatric internal medicine and its multi-disciplinarity.

Asphyxia↗
PubMed1987

Influence of lipid environment on insulin binding in cultured hepatoma cells.

The influence of alterations of plasma membrane physico-chemical properties on insulin binding have been characterized in an insulin-sensitive rat hepatoma cell line adapted to grow for several generations in culture medium enriched with linoleic acid (18:2) or with 25-hydroxycholesterol. The cells took up 18:2 and 25-hydroxycholesterol added to the culture medium, without exhibiting any sign of intolerance or intoxication. These compounds respectively increased and decreased membrane fluidity at 37 degrees C. The cells demonstrated extensive changes in insulin binding parameters in response to experimental modifications of their membrane lipid composition. When determined at 4 degrees C, insulin receptors were present in the control cells at 136,000 sites/cell but this fell to 111,000 (P less than 0.05) in cells enriched in 18:2, and rose to 176,000 (P less than 0.001) in hydroxysterol-grown cells. According to a two-site model, the main effect of 18:2 was a significant increase of the number of high-affinity sites with a concomitant decrease of low-affinity sites. The hydroxysterol had the opposite effects on these parameters. The high-affinity insulin binding capacity of the hepatoma cells was affected by lipid supplementation in a similar way, whether it was determined at 4 degrees C or at 37 degrees C. Assuming a negative cooperativity model, 18:2 enhanced the degree of negative cooperativity among the sites, while 25-hydroxycholesterol reduced it. The time-course of insulin-induced receptor down-regulation was accelerated in the cells enriched in polyunsaturated fatty acids, but reduced in cells exposed to 25-hydroxycholesterol. These insulin-binding alterations cannot be directly related to modifications of cellular growth rate, receptor internalization or membrane fluidity per se, and are discussed as being more likely due to membrane lipid composition than to overall cell metabolism modifications.

Animals↗
PubMed1987

Modifications of cellular lipids induce insulin resistance in cultured hepatoma cells.

We altered the cellular lipid composition of an insulin sensitive rat hepatoma cell line through supplementation of the culture medium with linoleic acid (18:2) or 25-hydroxycholesterol, and we studied the effects on insulin stimulation of aminoacid transport system A and glycogen synthesis. The basal rate of sodium-dependent aminoisobutyric acid uptake was slightly reduced in hydroxysterol-treated cells and increased in 18:2-enriched cells. Maximal insulin stimulation of transport was decreased by about 40% in both 18:2 and 25-hydroxycholesterol modified cells, as compared to control cells. In addition to reduced responsiveness, the hydroxysterol-treated cells also showed a diminished sensitivity to insulin, as revealed by a right-shift of the dose-response curve leading to a ED50 of 1.2 X 10(-8) M (P less than 0.02), as compared to 2.45 X 10(-9) M in control cells and 2.13 X 10(-9) M in 18:2 enriched cells. Concerning glycogen synthesis, the basal rate was unaffected by 25-hydroxycholesterol supplementation and slightly reduced in cells enriched in 18:2. Maximal insulin stimulation of glycogen synthesis was reduced by about 40% in both types of lipid modified cells. 25-Hydroxycholesterol again provoked a decrease in sensitivity to insulin: the ED50 was enhanced to 4.9 X 10(-9) M (P less than 0.05), as compared to 1.25 X 10(-9) M in control cells and 1.57 X 10(-9) M in 18:2-supplemented cells. Taken together with the previously reported changes of insulin binding to lipid modified hepatoma cells (Bruneau et al. (1987) Biochim. Biophys. Acta 928, 287-296) our results demonstrate an influence of alterations of the cellular lipid composition on both binding and biological actions of insulin, leading to an insulin-resistant state. Divergences between insulin binding and action were obtained and it was suggested that post-binding events may be responsible for the observed changes. Our findings may be relevant to experimental and clinical states of insulin resistance.

Amino Acids↗
PubMed1987

[Toxic epidermal necrolysis in children (Lyell's syndrome). Apropos of 18 cases].

The authors report 18 children with toxic epidermal necrolysis (T.E.N.). The clinical and laboratory signs, the development of complications and sequelae and the drugs presumed to be responsible are compared with those of T.E.N. in adults. The onset was generally marked by a influenza-like state with development of mucosal signs between the first and the seventh days. The lips and buccal cavity were involved in 16 cases and the eyelids and conjunctiva were involved in 15 cases. Epidermal loss occurred after a variable interval of between one and eight days after the appearance of the erythema. The severity of the epidermal loss, expressed as a percentage of the body surface area, was a poor prognostic factor. Hypoproteinaemia was the most frequently observed laboratory abnormality. The complications were infectious and the 2 deaths in this series were due to septicaemia. Ocular complications were also observed: keratitis, responsible for sequelae such as distichiasis, conjunctival adhesions, sicca syndrome. As in adults, these children were frequently taking multiple drugs. Among the drugs prescribed during the classical interval of imputability, two drugs were particularity noted: phenobarbital and oxyphenbutazone. Treatment should only be undertaken in a specialized unit and is based on the principles of intensive care of burns patients: control of hypovolemia and infection. Ocular sequelae should be prevented by local treatments several times a day.

Child↗
PubMed1987

[Hemodynamic study of obstructive lesions of the internal carotid artery: value of coupled measurement of regional cerebral blood flow and volume].

A study of 130 patients having presented either a transient ischemic attack or a completed stroke, or admitted for an asymptomatic carotid stenosis, allowed the following investigations: CT-scan, doppler, angiography, measurement of the regional cerebral blood flow (rCBF) by the study of 133Xe clearance (Novocerebrograph (R)), and measurement of the regional cerebral blood volume (rCBV) made by gamma emission tomography after autotransfusion of 99m Tc-labeled erythrocytes with an Elscint Apex 415 ECT (R) camera. Our aim was to look in which case a rCBF and/or a rCBV interhemispheric asymmetry was observed, by comparing the previous hemodynamic parameters with clinical, CT-scan and angiographic data. Although a rCBF and/or a rCBV asymmetry appeared more often among patients presenting with infarction than among those of the asymptomatic category, this does not seem specific for any clinical grade. The same statement applies to the comparison between hemodynamic parameters and CT data. The arterial lesions were classified in 4 groups: no stenosis (12 cases), uni or bilateral moderate carotid stenosis (40 cases), unilateral severe carotid stenosis or occlusion (65 cases), bilateral carotid severe stenosis or occlusion (13 cases). We observed a rCBF asymmetry among some patients in the 4 groups, although this was more frequent among the two latter groups. Nevertheless no case of a rCBV asymmetry was observed in the 2 first groups. Such an asymmetry was present in 31 percent of the patients belonging to the two latter groups. In patients of the third group the asymmetry was always due to a relative increase of rCBV beyond the carotid lesion.(ABSTRACT TRUNCATED AT 250 WORDS)

Arterial Occlusive Diseases↗
PubMed1987

[A case of botulism in a 11-month-old infant].

We report a case of botulism in a 11 month-old infant. Hypotonia complicated by progressive bulbar paralysis revealed the disease. Botulism B toxin was present in serum on the 8th day of the disease. On the occasion of this case report the clinical, diagnostic, epidemiological and pathophysiologic aspects of infant botulism are reviewed. The relationship between sudden infant death and botulism is discussed.

Botulism↗
PubMed1987

The effect of long-term almitrine therapy on sleep hypoxaemia in patients with chronic airways obstruction.

Sleep hypoxaemia was investigated in 11 patients. The patients were randomly assorted to receive almitrine bismesylate therapy or identical placebo tablets. Almitrine therapy was associated with an increase of daytime PaO2, mean SaO2 awake and during sleep, and less time when SaO2 fell below 90% during sleep. The number of desaturation episodes and lowest SaO2 were unaffected.

Administration, Oral↗
PubMed1986

Decreased membrane "fluidity" of T lymphocytes from untreated patients with Hodgkin's disease.

Plasma membrane "fluidity" of peripheral blood T lymphocytes from untreated patients with Hodgkin's disease (HD) and healthy controls was studied using the fluorescent probes 1,6-diphenyl-1,3,5-hexatriene (DPH) and 1-(4(trimethylamino)phenyl)-6-phenyl-1,3,5-hexatriene (TMA-DPH). In 13 consecutive patients a significant increase of T lymphocyte plasma membrane microviscosity was observed with both DPH and TMA-DPH. These alterations seemed unrelated to the cholesterol (Chol) and phospholipid (PL) content of HD T lymphocytes since the Chol/PL ratio was comparable in both HD and control cells. Since prostaglandin E2 (PGE2) from monocytic origin has been claimed to be responsible for the impairment of cell-mediated immunity (CMI) associated with HD, we studied the effect of exogeneously added PGE2 (0.1 microM) on control subjects T lymphocyte membrane "fluidity". Using the fluorescent probe DPH and the spin labelled fatty acid probe 16 NMS for electron paramagnetic resonance study, we observed a PGE2-induced fluidization of control T lymphocyte membranes which is specifically located in the inner part of the plasma membrane, whereas the plasma membrane surface seemed unaffected by PGE2 as judged by the TMA-DPH probe. Thus, PGE2 does not appear to be responsible for the alterations of T lymphocyte membranes observed in HD. Intrinsic alterations and/or other mediators might be involved.

Adult↗
PubMed1986

Hemodynamic study of internal carotid artery stenosis and occlusion: value of combined isotopic measurements of regional cerebral blood flow and blood volume.

The assessment of the intracranial hemodynamic consequences of obstructive lesions of the carotid artery by measuring resting rCBF is inadequate because cerebral blood flow may remain constant in spite of significant drops in the intraluminal pressure due to autoregulation. Moreover, flow may be permanently decreased following cerebral infarction, even if the arterial anatomical conditions have resumed their normal state because of the decreased metabolic demand of an infarcted area. Measurement of the regional cerebral blood volume (rCBV) helps with the hemodynamic assessment of these conditions, since there is a linear and inverse relationship between intraarterial pressure and intracranial blood volume. In 24 patients exhibiting various carotid and ischemic brain lesions we studied both rCBF and rCBV. The latter is a comparative measure between hemispheres obtained by single photon emission tomography after autotransfusion of 99m Technetium labeled erythrocytes. There was no correlation between rCBF and clinical status, CT scan or arterial lesions. There was no correlation between rCBV and clinical status or CT scan. There was, however, an interesting correlation between rCBV and the severity of the arterial lesion. The rCBV was symmetrical in all patients with normal or moderately stenotic carotid arteries before and after operation. In some patients with severe unilateral stenosis or occlusion, there was a significant relative increase of rCBV in the hemisphere downstream from the lesion, which disappeared after surgery (endarterectomy or extra-intracranial bypass). In some patients with severe and bilateral carotid lesions, we noted an asymmetry in rCBV that disappeared after a unilateral operation. Other patients with similar lesions develop asymmetry only after an operation that resulted in a relative increase in rCBV in the hemisphere supplied by the non-operated artery. In conclusion analysis of these results suggests that in this series of patients, rCBV modifications were the consequence of cerebral autoregulation distal to the arterial lesions and provided satisfactory assessment of hemodynamic improvement after surgical repair.

Adult↗
PubMed1986

[Treatment of the sleep apnea syndrome by continuous positive pressure].

Six patients with severe sleep apnoea syndrome (SAS) were treated for one night by continuous positive pressure by the nasal route (PPC). The six patients tolerated the treatment well. During the course of the night, while receiving PPC, we noticed that in five patients there was a normalisation of the indices of apnoea, a disappearance of the episodes of desaturation and a re-organisation of sleep pattern. In one patient PPC was effective on obstructive apnoea, but did not make all mixed and central apnoea disappear. After a 4 or 5 day trial in hospital, 4 patients have now been treated at home for at least 6 months. PPC remains effective and well tolerated in the long term. As it is well tolerated and effective, PPC may be used to treat patients with SAS at an earlier stage than that at which tracheotomy is proposed.

Aged↗